PROBLEM TO BE SOLVED: To provide a fluid sterilizer capable of exchanging a component easily.SOLUTION: The fluid sterilizer of the embodiment is equipped with a channel housing chamber, a light source housing chamber, and a cooling water passage. The channel housing chamber accommodates a channel pipe for flowing a fluid and a channel part provided at an outer periphery of a channel pipe including a reflector plate for reflecting ultraviolet ray toward the channel pipe. The light source housing chamber accommodates a light source for irradiation of ultraviolet ray toward the inside of the channel pipe. The cooling water passage is provided around the light source housing chamber and a cooling water flows therein. Also, the channel housing chamber and the light source housing chamber respectively include a connection port for flowing a dry fluid from the outside.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2020,JPO&INPIT【課題】部品の交換を容易にすること。【解決手段】実施形態に係る流体殺菌装置は、流路収容室と、光源収容室と、冷却水路とを具備する。流路収容室は、流体を流すための流路管と流路管の外周に設けられ流路管に向かって紫外線を反射する反射板とを有する流路部を収容する。光源収容室は、流路管内に向けて紫外線を照射する光源を収容する。冷却水路は、光源収容室の周囲に設けられ、冷却水が流れる。また、流路収容室および光源収容室は、外部から乾燥流体を流すための接続口をそれぞれ有する。【選択図】図2